(a) A Bank shall require each member to maintain a minimum investment in the capital stock of the Bank, both as a condition to becoming and remaining a member of the Bank and as a condition to transacting business with the Bank or obtaining advances and other services from the Bank. The amount of the required minimum investment shall be determined in accordance with the Bank's capital plan and shall be sufficient to ensure that the Bank remains in compliance with its regulatory capital requirements. A Bank shall require each member to maintain its minimum investment for as long as the institution remains a member of the Bank and shall require each member and former member to maintain its minimum investment for as long as the institution engages in any activity with the Bank for which the capital plan requires the institution to maintain capital stock.

(b) A Bank may establish the minimum investment as a percentage of the total assets of an institution, as a percentage of the advances outstanding to that institution, as a percentage of any other business activity conducted with the institution, on any other basis that is approved by the Director, or any combination thereof.

(c) A Bank may require that the minimum investment requirement be satisfied through the purchase of either Class A or Class B stock, or through the purchase of one or more combinations of Class A and Class B stock that have been authorized by the board of directors of the Bank in its capital plan. A Bank, in its discretion, may establish a lower minimum investment to the extent the requirement is met through investment in Class B stock than if the requirement is met through investment in Class A stock, provided that such reduced investment provides sufficient capital for the Bank to remain in compliance with its regulatory capital requirements.

(d) Each member, or if applicable, former member, of a Bank shall at all times maintain an investment in the capital stock of the Bank in an amount that is sufficient to satisfy the minimum investment required under the Bank's capital plan.